Drive Control Device and Method for Electronic Expansion Valve

ABSTRACT

A drive control device and method for an electric expansion valve is disclosed. In the disclosure, before applying a drive pulse signal corresponding to a rotary pulse number to a motor of the electronic expansion valve, a secondary positioning is performed on a relative position between stator magnetic field of the motor and rotor magnetic field of the motor by applying a holding current of a first duration time to the motor, applying an pulse signal of an additional pulse number to the motor, and applying a holding current of a second duration time to the motor, and a same secondary positioning operation is also performed on the motor after applying the drive pulse signal corresponding to the rotary pulse number to the motor of the electronic expansion valve, which ensures that the electronic expansion valve operates according to the drive pulse signal corresponding to the rotary pulse number.

TECHNICAL FIELD

The disclosure relates to an electronic expansion valve technique, andin particular to a drive control device and method for an electronicexpansion valve.

BACKGROUND ART

Along with the development of science and technology, the electronicexpansion valve has been commonly used in the field of inverter airconditioners. It is a step motor electronic expansion valve that isgenerally used in the field of air conditioners. The electronicexpansion valve comprises a step motor and a valve body, and the openingof the valve body is controlled by the rotation of the step motor. Thedriving circuit of the step motor is connected with the step motorthrough a drive wire. When the electronic expansion valve is to bedriven, the controller sends a pulse control signal to the drivingcircuit to thereby drive the step motor to rotate to make the valve bodyreach a corresponding opening.

However, at present, the application of the electronic expansion valvein the field of inverter air conditioners mainly relates to thetechnique of how to control the rotation of the step motor according tothe change of the temperature and pressure to thereby adjust the openingof the valve body of the electronic expansion valve. To be specific, inthe use of the electronic expansion valve in the prior art, the pressureand temperature are sampled by a temperature and pressure sensor, andthe target opening of the electronic expansion valve is controlled basedon the collected pressure and temperature and according to a controlalgorithm. The CPU obtains the opening desired by the electronicexpansion valve by calculation and converts it into a correspondingpulse signal, which drives the step motor of the electronic expansionvalve by a driver, and the step motor drives the valve body to rotate tothereby adjust the opening of the electronic expansion valve. Asmentioned above, many mature techniques, which are not greatlydifferent, are existing in terms of the macro-control of the valve bodyopening of the electronic expansion valve, but few of them relate to thecontrol details of the electronic expansion valve, i.e., the drivetechnique of starting and stopping the electronic expansion valveitself. Due to the overlook in terms of the control details, that thedrive is out of step generally appears in the electronic expansion valvein use, and the electronic expansion valve cannot be effectively drivenand cannot effectively keep the current opening and the like.

Especially, the control manner of the start of the electronic expansionvalve in the prior art is as follows: after the electronic expansionvalve was stopped last time, and when the target pulse signal changes,the electronic expansion valve is directly turned on and off at a normaloperating rate directly from the current pulse signal. There is notanything wrong in such drive manner of the electronic expansion valve innormal circumstances. However, there are two circumstances that willrender the electronic expansion valve unable to effectively act. Thefirst circumstance is that when the electronic expansion valve has notbeen used over a long period of time or there is oil or a foreign matteradhered or blocked in the valve body, the electronic expansion valvegenerally cannot be effectively driven due to an insufficient startingtorque of the motor, which causes a case of slip and step-out, so thatthe electronic expansion valve cannot be effectively turned on and off.The second circumstance is that after the stop of the motor of theelectronic expansion valve, a current is applied to the stop pulsesignal of the electronic expansion valve, thereby making the magneticfield between the stator and the rotor of the motor of the electronicexpansion valve form a holding torque, so that the coil of theelectronic expansion valve still keeps the rotor in a state when it isstopped in the case of not being electrified. However, in actualcircumstances, under the impact of the refrigerant pressure and thelike, the rotor of the motor of the electronic expansion valve will beinevitably displaced. The start is performed according to the pulseposition where the electronic expansion valve was stopped last time inthe case that the rotor is displaced, and the case that the start is outof step is generally caused due to the deviation of the position of therotor.

In addition, the control manner of the stop of the electronic expansionvalve in the prior art is as follows: generally, after the electronicexpansion valve operates to reach the target pulse, a current of 50 msor more is further continuously applied to the electronic expansionvalve to increase the holding torque of the electronic expansion valveto prevent the S pole or the N pole of the rotor magnetic field of themotor of the electronic expansion valve from being misplaced from the Npole or S pole of the stator magnetic field. However, in actualcircumstances, it still hardly ensure that the S pole or the N pole ofthe rotor magnetic field of the motor of the electronic expansion valveis not misplaced from the N pole or S pole of the stator magnetic fieldonly by further continuously applying a current of 50 milliseconds ormore to the electronic expansion valve after the electronic expansionvalve operates to reach the target pulse.

Thus, the drive technique of starting and stopping the electronicexpansion valve in the prior art still hardly overcome the defect thatthe electronic expansion valve cannot be effectively driven due to aninsufficient starting torque of the motor and the defect that the startis out of step due to the deviation of the relative position between therotor and the stator, and cannot ensure that the valve body opening ofthe electronic expansion valve is correctly controlled. However, in thefield of inverter air conditioners, especially in the field ofcommercial inverter-driven multi-split air conditioners, the opening ofthe electronic expansion valve has an irreplaceable function on thecontrol of the entire air conditioning system. Thus, whether or not theelectronic expansion valve can be correctly turned on, whether or notthe opening is proper and whether or not the current opening can be keptdecide the performance and reliability of the air conditioning system.And in order obtain a good performance and reliability, the drivetechnique capable of correctly driving the electronic expansion valve isthe key as for whether or not a product of an air conditioning system issuccessful.

Thus, there exists a need for a technique capable of effectivelycontrolling the start and stop of the electronic expansion valve toensure that the valve body opening of the electronic expansion valve iscorrect.

SUMMARY OF THE DISCLOSURE

The embodiments of the disclosure provide a technique capable ofeffectively controlling start and stop of an electronic expansion valveto ensure that a valve body opening of electronic expansion valve iscorrect.

According to one aspect of the disclosure, a drive control device for anelectronic expansion valve is provided. Before starting the electronicexpansion valve, a secondary positioning is performed on the motor ofthe electronic expansion valve to overcome the defect that theelectronic expansion valve cannot be effectively driven due to aninsufficient starting torque of the motor and the defect that the startis out of step due to the deviation of the relative position between therotor and the stator, and further after applying a rotary pulse numberto the motor of the electronic expansion valve, a secondary positioningis performed on the motor of the electronic expansion valve again toenhance the torque of the motor to achieve that the rotor of the motorof the electronic expansion valve will not be displaced due to arefrigerant pressure change and the like after the stop of the motor.

The drive control device comprises: a processing unit for receiving adesired valve body opening signal of the electronic expansion valve anddetermining a desired valve body opening pulse number according to thedesired valve body opening signal, and obtaining a rotary pulse numberof a pulse signal required to rotate the motor of the electronicexpansion valve based on the desired valve body opening pulse number anda current valve body opening pulse number; a driving signal generatingcircuit for producing an additional pulse signal of a predeterminedpulse number under control of the processing unit and producing a drivepulse signal of a corresponding pulse number according to the rotarypulse number, and producing a holding current of a predeterminedduration time under control of the processing unit; and a drivingcircuit for performing power amplifications on the additional pulsesignal and the drive pulse signal respectively and applying them to themotor to rotate the motor, and performing a power amplification on theholding current of the predetermined duration time outputted from thedriving signal generating circuit and applying it to the motor toproduce a torque that achieves positioning a relative position betweenstator and rotor magnetic fields of the motor.

Wherein the driving signal generating circuit producing a holdingcurrent of a predetermined duration time under control of the processingunit comprises: the driving signal generating circuit producing a firstholding current of a first predetermined duration time when theprocessing unit determines that the desired valve body opening pulsenumber is not equal to the current valve body opening pulse number; andthe driving signal generating circuit producing a second holding currentof a second predetermined duration time after the driving circuit drivesthe motor according to an additional pulse signal of a firstpredetermined pulse number.

Wherein the driving signal generating circuit producing a holdingcurrent of a predetermined duration time under control of the processingunit comprises: the driving signal generating circuit producing a thirdholding current of a third predetermined duration time after the drivingcircuit drives the motor according to the drive pulse signal; and thedriving signal generating circuit producing a fourth holding current ofa fourth predetermined duration time after the driving circuit drivesthe motor according to an additional pulse signal of a secondpredetermined pulse number.

According to another aspect of the disclosure, a drive control methodfor an electronic expansion valve is provided. The method performs,before starting the electronic expansion valve, a secondary positioningon the motor of the electronic expansion valve to overcome the defectthat the electronic expansion valve cannot be effectively driven due toan insufficient starting torque of the motor and the defect that thestart is out of step due to the deviation of the relative positionbetween the rotor and the stator, and the method can further perform,after applying a rotary pulse number to the motor of the electronicexpansion valve, a secondary positioning on the motor of the electronicexpansion valve again to enhance the torque of the motor to achieve thatthe rotor of the motor of the electronic expansion valve will not bedisplaced due to a refrigerant pressure change and the like after thestop of the motor. The drive control method comprises the steps of:receiving a desired valve body opening signal of the electronicexpansion valve, and determining a desired valve body opening pulsenumber according to the desired valve body opening signal; applying afirst holding current of a first predetermined duration time to themotor to produce a torque that achieves positioning a relative positionbetween stator and rotor magnetic fields of the motor when the desiredvalve body opening pulse number is different from a current valve bodyopening pulse number; applying a first additional pulse signal of afirst predetermined pulse number to the motor of the electronicexpansion valve after performing a power amplification thereon, and thenapplying a second holding current of a second predetermined durationtime to the motor to produce a torque that achieves positioning arelative position between stator and rotor magnetic fields of the motor;and determining a rotary pulse number that rotates the motor accordingto the desired valve body opening pulse number and the current valvebody opening pulse number, producing a drive pulse signal correspondingto the rotary pulse number based on the rotary pulse number, andapplying the drive pulse signal to the motor of the electronic expansionvalve after performing a power amplification thereon.

Wherein receiving a desired valve body opening signal of the electronicexpansion valve and determining a desired valve body opening pulsenumber according to the desired valve body opening signal comprises:using, if the desired valve body opening signal is a pulse number, thepulse number as the desired valve body opening pulse number; andconverting, if the desired valve body opening signal is an angle signal,the angle signal into a pulse number of a pulse signal corresponding tothe angle signal according to a predetermined algorithm, and using it asthe desired valve body opening pulse number.

The drive control method further comprises: storing the desired valvebody opening pulse number in the memory to serve as the current valvebody opening pulse number.

Wherein, after producing a drive pulse signal corresponding to therotary pulse number based on the rotary pulse number, and applying thedrive pulse signal to the motor of the electronic expansion valve afterperforming a power amplification thereon, the method further comprises:applying a third holding current of a third predetermined duration timeto the motor to produce a torque that achieves positioning a relativeposition between stator and rotor magnetic fields of the motor.

Wherein, after applying a third holding current of a third predeterminedduration time to the motor to produce a torque that achieves positioninga relative position between stator and rotor magnetic fields of themotor, the method further comprises: applying a second additional pulsesignal of a second predetermined pulse number to the motor of theelectronic expansion valve, and then applying a fourth holding currentof a fourth predetermined duration time to the motor to produce a torquethat achieves positioning a relative position between stator and rotormagnetic fields of the motor.

According to a further aspect of the disclosure, a drive control methodfor an electronic expansion valve is provided. The drive control methodperforms, after applying a rotary pulse number to the motor of theelectronic expansion valve, a secondary positioning on the motor of theelectronic expansion valve again to enhance the torque of the motor toachieve that the rotor of the motor of the electronic expansion valvewill not be displaced due to a refrigerant pressure change and the likeafter the stop of the motor; and the drive control method can alsoapply, before starting the electronic expansion valve, a current of apredetermined duration time to the electronic expansion valve to performa primary positioning on the motor to overcome the defect that theelectronic expansion valve cannot be effectively driven due to aninsufficient starting torque of the motor. The drive control methodcomprises the steps of: receiving a desired valve body opening signal ofthe electronic expansion valve, and determining a desired valve bodyopening pulse number according to the desired valve body opening signal;determining a rotary pulse number that rotates the motor of theelectronic expansion valve according to the desired valve body openingpulse number and a current valve body opening pulse number, producing adrive pulse signal corresponding to the rotary pulse number based on therotary pulse number, and applying the drive pulse signal to the motor ofthe electronic expansion valve after performing a power amplificationthereon; applying a third holding current of a third predeterminedduration time to the motor after performing a power amplificationthereon to produce a torque that achieves positioning a relativeposition between stator and rotor magnetic fields of the motor; andapplying an additional pulse signal of a second predetermined pulsenumber to the motor of the electronic expansion valve after performing apower amplification thereon, and then applying a fourth holding currentof a fourth predetermined duration time to the motor after performing apower amplification thereon to produce a torque that achievespositioning a relative position between stator and rotor magnetic fieldsof the motor.

Wherein receiving a desired valve body opening signal of the electronicexpansion valve and determining a desired valve body opening pulsenumber according to the desired valve body opening signal comprises:using, if the desired valve body opening signal is a pulse number, thepulse number as the desired valve body opening pulse number; andconverting, if the desired valve body opening signal is an angle signal,the angle signal into a pulse number of a pulse signal corresponding tothe angle signal according to a predetermined algorithm, and using it asthe desired valve body opening pulse number.

Wherein, before determining a rotary pulse number making the motor ofthe electronic expansion valve rotate according to the desired valvebody opening pulse number and a current valve body opening pulse number,the method further comprises: applying a first holding current of afirst predetermined duration time to the motor after performing a poweramplification thereon to produce a torque that achieves positioning arelative position between stator and rotor magnetic fields of the motor.

Wherein the current valve body opening pulse number is stored in amemory.

The drive control method further comprises: storing the desired valvebody opening pulse number in the memory to serve as the current valvebody opening pulse number.

Wherein each of the first, second, third and fourth duration times is 50milliseconds to 1 second.

Wherein the first and second predetermined pulse numbers are 1.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of the structure of the electronicexpansion valve equipped with a drive control device of the embodimentof the disclosure;

FIG. 2 shows a flow chart of the drive control method for the electronicexpansion valve according to one embodiment of the disclosure;

FIG. 3 shows a flow chart of the drive control method for the electronicexpansion valve according to another embodiment of the disclosure;

FIG. 4 shows a flow chart of the drive control method for the electronicexpansion valve according to a further embodiment of the disclosure.

DETAILED DESCRIPTION

In order to make the object, the technical solutions and the advantagesof the disclosure clearer, the disclosure is further described in detailbelow by referring to the figures and enumerating preferred embodiments.However, it should be noted that many details are only listed in theDescription for making the readers have a thorough understanding of oneor more aspects of the disclosure, and these aspects of the disclosurecan be also achieved even without these specific details.

The advantages of the electronic expansion valve make the electronicexpansion valve be widely applied in the air conditioners, especiallythe inverter-driven multi-split air conditioners. Generally, the airconditioner and the inverter-driven multi-split air conditioner are bothprovided with an electronic expansion valve on the outdoor machine andthe indoor machine, respectively. During refrigeration, the electronicexpansion valve of the outdoor machine is fully opened, and theelectronic expansion valve of the indoor machine performs a control ofexhaust superheat, so that the system and the compressor are located ina stable and reliable operating area. During heating, the electronicexpansion valve of the outdoor machine performs a control of exhaustsuperheat, and the electronic expansion valve of the indoor machineperforms a refrigerant quality distribution according to the capacitiesof the respective indoor machines, so that the heating effects of therespective indoor machines are optimized. In the refrigerating orheating process of the air conditioner, the specific technical measureof adjusting the valve body opening of the electronic expansion valveaccording to the temperature and pressure to thereby control thetemperature has been described a lot in the prior art, and details areomitted herein. In the disclosure, the electronic expansion valve refersto an electronic expansion valve using a DC motor technique.

According to the disclosure, in order to overcome the defect that theelectronic expansion valve cannot be effectively driven due to aninsufficient starting torque of the motor and the defect that the startis out of step due to the deviation of the relative position between therotor and the stator, a secondary positioning is performed on theposition between the rotor and the stator both at the start and the stopof the electronic expansion valve. To sum up, at the start of theelectronic expansion valve, a holding current of a predeterminedduration time is firstly applied to the motor of the electronicexpansion valve, a magnetic field is produced between the rotor and thestator of the motor, and a primary positioning is performed on theposition between the rotor and the stator using a torque produced bythis magnetic field. Then, an additional pulse signal of a predeterminedpulse number is applied to the motor to rotate the motor by a tinyangle, next another holding current of a predetermined duration time isapplied to the motor again, and thus a secondary positioning isperformed using a torque produced by the magnetic field between therotor and the stator. Next, a target pulse signal is applied to themotor to rotate the motor by a corresponding angle. Alternatively, afterthe target pulse signal and when the motor is stopped, a holding currentof a predetermined duration time can be also firstly applied to themotor of the electronic expansion valve, a magnetic field is producedbetween the rotor and the stator of the motor, and a primary positioningis performed on the position between the rotor and the stator using atorque produced by this magnetic field. Next, an additional pulse signalof a predetermined pulse number is applied to the motor to rotate themotor by a tiny angle, next another holding current of a predeterminedduration time is applied to the motor again, and a secondary positioningis performed using a torque produced by the magnetic field between therotor and the stator.

The specific implementation modes of the disclosure are described indetailed below:

FIG. 1 is a schematic diagram of the structure of the electronicexpansion valve equipped with a drive control device of the embodimentof the disclosure. As shown in FIG. 1, the electronic expansion valvecomprises a drive control device and a body part. The body partcomprises a motor 14 and a valve body 15. Those skilled in the artunderstand that the drive control device can be integrated with the bodypart, or can be also an independent component that is completelyseparate from the body part. The drive control device as shown in FIG. 1comprises a processing unit 10, a driving signal generating circuit 11and a driving circuit 12.

The processing unit 10 receives a desired valve body opening signal ofthe electronic expansion valve. The desired valve body opening signal issent out by a master controller (not shown) of the air conditioningsystem. The desired valve body opening signal can be an angle signaldenoting the valve body opening, or a pulse number denoting a pulsesignal corresponding to the angle signal of the valve body opening. Theprocessing unit 10 determines the desired valve body opening pulsenumber according to the desired valve body opening signal. To bespecific, when the desired valve body opening signal is a pulse number,the processing unit 10 uses the pulse number as the desired valve bodyopening pulse number; and when the desired valve opening signal is anangle, the processing unit 10 converts the angle signal into a pulsenumber of a pulse signal corresponding to the angle signal denoting thevalve body opening according to a predetermined algorithm, and uses itas the desired valve body opening pulse number. The processing unit 10determines a rotary pulse number of a pulse signal required to rotatethe motor of the electronic expansion valve according to the desiredvalve body opening pulse number and the current valve body opening pulsenumber, wherein the rotary pulse number is the difference between thedesired valve body opening pulse number and the current valve bodyopening pulse number. In the disclosure, the current valve body openingpulse number is stored in a memory 13, and the memory 13 can be locatedinside the processing unit 11, and can also serve as an independentcomponent outside the processing unit 11. The driving signal generatingcircuit 11 produces a drive pulse signal of a corresponding pulse numberaccording to the rotary pulse number determined by the processing unit10. When the processing unit 10 determines that an additional pulsesignal of a predetermined pulse number is to be produced, the drivingsignal generating circuit 11 produces the additional pulse signal of thepredetermined pulse number. The processing unit 10 determines whether toindicate the driving signal generating circuit 11 to produce a holdingcurrent and an additional pulse signal of a predetermined pulse number.To be specific, when the processing unit 10 determines that the desiredvalve body opening pulse number is different from the current valve bodyopening pulse number, the processing unit 10 controls the driving signalgenerating circuit 11 to firstly output a first holding current of afirst predetermined duration time; then the driving signal generatingcircuit 11 outputs an additional pulse signal of a first predeterminedpulse number; and next the processing unit 10 controls the drivingsignal generating circuit 11 output a second holding current of a secondpredetermined duration time. The processing unit 10 monitors the outputsignal of the driving signal generating circuit 11, and when the outputsignal is the drive pulse signal of the rotary pulse number, theprocessing unit 10 controls the driving signal generating circuit 11 tooutput a third holding current of a third predetermined duration timeafter the drive pulse signal of the rotary pulse number; then thedriving signal generating circuit 11 outputs an additional pulse signalof a second predetermined pulse number; and the processing unit 10controls the driving signal generating circuit 11 to output a fourthholding current of a fourth predetermined duration time. The signaloutputted from the driving signal generating circuit 11 is transmittedto the driving circuit 12. The driving circuit 12 performs a poweramplification on the signal from the driving signal generating circuitand applies it to the motor 14, so that the motor 14 performs acorresponding action. To be specific, when the signal outputted from thedriving signal generating circuit 11 is a pulse signal, the drivingcircuit 12 drives the motor 14 to rotate by an angle corresponding tothe pulse number of the pulse signal; and when the signal outputted fromthe driving signal generating circuit 11 is a holding current signal,the driving circuit 12 produces a torque that positions the stator andthe rotor of the motor between the stator and rotor magnetic fields ofthe motor 14.

Every time after the motor is driven to rotate according to the pulsesignal of the rotary pulse number, the processing unit 10 stores thedesired valve body opening pulse number to serve as the current valvebody opening pulse number.

In the disclosure, the holding current is a direct current.

FIG. 2 shows a flow chart of the drive control method for the electronicexpansion valve according to one embodiment of the disclosure. As shownin FIG. 2, in the step 201, the processing unit 10 receives a desiredvalve body opening signal of the electronic expansion valve, and obtainsa desired valve body opening pulse number from the desired valve bodyopening signal. As mentioned above, the desired valve body openingsignal is sent out by a master controller of the air conditioningsystem. If the desired valve body opening signal is a pulse number, theprocessing unit 10 uses this pulse number as the desired valve bodyopening pulse number. If the desired valve body opening signal is anangle signal, the processing units 10 converts this angle signal into apulse number of a pulse signal corresponding to the angle signaldenoting the valve body opening according to a predetermined algorithm,and uses it as the desired valve body opening pulse number.

Next, in the step 202, the processing unit 10 reads a current valve bodyopening pulse number from the memory. The processing unit 10 comparesthe desired valve body opening pulse number with the current valve bodyopening pulse number (step 203), and determines a rotary pulse number ofa pulse signal required to rotate the motor of the electronic expansionvalve when the two pulse numbers are different. If the desired valvebody opening pulse number is the same as the current valve body openingpulse number, the flow proceeds to the step 210. If the desired valvebody opening pulse number is different from the current valve bodyopening pulse number, the processing unit 10 controls the driving signalgenerating circuit 11 to output a first holding current of a firstpredetermined duration time to the driving circuit 12, which current isapplied to the motor of the electronic expansion valve after undergoinga power amplification by the driving circuit 12, a magnetic field isaccordingly produced between the rotor and the stator of the motor, anda primary positioning is performed on a relative position between rotormagnetic field of the motor and stator magnetic field using a torqueproduced by this magnetic field (step 204). Then, the driving signalgenerating circuit 11 outputs an additional pulse signal of a firstpredetermined pulse number under control of the processing unit 10, andthis additional pulse signal acts on the motor of the electronicexpansion valve after undergoing a power amplification by the drivingcircuit 12 to rotate the motor by a tiny angle (step 205). In the step206, the processing unit 10 controls the driving signal generatingcircuit 11 again to output a second holding current of a secondpredetermined duration time, which current is applied to the motor ofthe electronic expansion valve after undergoing a power amplification bythe driving circuit 12, a magnetic field is thus produced between therotor and the stator of the motor, and a secondary positioning isperformed on a relative position between rotor and stator magneticfields using a torque produced by this magnetic field.

Next, the processing unit 10 controls the driving signal generatingcircuit 11 to produce a rotary pulse signal corresponding to the rotarypulse number according to the determined rotary pulse number, and inputsit into the driving circuit 12. The rotary pulse signal is applied tothe motor of the electronic expansion valve after undergoing a poweramplification by the driving circuit 12 to rotate the motor by an anglecorresponding to the rotary pulse number (step 207). In the step 208,the processing unit 10 indicates the driving signal generating circuit11 to produce an additional current, which current is applied to themotor after undergoing a power amplification by the driving circuit 12to produce a torque. In this embodiment, the step 208 is not necessary.In the step 209, the processing unit 10 stores the desired valve bodyopening pulse number in the memory to serve as the current valve bodyopening pulse number, and the flow ends at the step 210.

In this embodiment, the first duration time and the second duration timecan be the same or different, but are both at least 50 milliseconds.Alternatively, both times can be 60 milliseconds, 70 milliseconds, 80milliseconds, 90 milliseconds, 100 milliseconds, etc. However, in ordernot to overheat the motor, the first duration time and the secondduration time had better not exceed 1 second.

In this embodiment, the first predetermined pulse number is preferably1.

As is well known, according to the characteristics of the electronicexpansion valve, the slower the driving rate of the motor is, the largerthe excitation torque of the motor is. A large torque contributes to theovercoming of the resistance produced for the reason that the electronicexpansion valve has not been used over a long period of time or there isoil or a foreign matter adhered or blocked in the valve body at thestart of the motor, so that a relative position of the rotor and thestator of the motor can be positioned. Thus, in this embodiment, inorder to overcome the defect that the electronic expansion valve cannotbe effectively driven due to an insufficient starting torque of themotor and the defect that the start is out of step due to the deviationof the relative position between the rotor and the stator, beforestarting the motor according to the rotary pulse number, firstly aholding current of a first duration time is applied to the motor, then apulse signal of an additional pulse number is applied to the motor, andfurther a holding current of a second duration time is applied to themotor. In this case, a large excitation torque is produced on the motorusing a secondarily applied holding current of a duration time, whichovercomes the resistance of the motor and operates twice positioning ofa relative position between the rotor and the stator of the motor. Inthis case, when a pulse signal corresponding to the rotary pulse numberis applied to the motor, the valve body opening of the electronicexpansion valve can be correctly controlled.

FIG. 3 shows a flow chart of the drive control method for the electronicexpansion valve according to another embodiment of the disclosure. Inthe step 301, as in the step 201, the processing unit 10 receives adesired valve body opening signal of the electronic expansion valve, andobtains a desired valve body opening pulse number from the desired valvebody opening signal. Next, in the step 302, the processing unit 10 readsa current valve body opening pulse number from the memory. Theprocessing unit 10 compares the desired valve body opening pulse numberwith the current valve body opening pulse number (step 303), anddetermines a rotary pulse number of a pulse signal required to rotatethe motor of the electronic expansion valve when the two pulse numbersare different. If the desired valve body opening pulse number is thesame as the current valve body opening pulse number, the flow proceedsto the step 312. If the desired valve body opening pulse number isdifferent from the current valve body opening pulse number, theprocessing unit 10 controls the driving signal generating circuit 11 tooutput a first holding current of a first predetermined duration time tothe driving circuit 12, which current is applied to the motor of theelectronic expansion valve after undergoing a power amplification by thedriving circuit 12, a magnetic field is produced between the rotor andthe stator of the motor, and a primary positioning is performed on aposition between the rotor and the stator using a torque produced bythis magnetic field (step 304). Then, the driving signal generatingcircuit 11 outputs an additional pulse signal of a first predeterminedpulse number under control of the processing unit 10, and thisadditional pulse signal acts on the motor of the electronic expansionvalve after undergoing a power amplification by the driving circuit 12to rotate the motor by a tiny angle (step 305). In the step 306, theprocessing unit 10 controls the driving signal generating circuit 11again to output a second holding current of a second predeterminedduration time, which current is applied to the motor of the electronicexpansion valve after undergoing a power amplification by the drivingcircuit 12, a magnetic field is produced between the rotor and thestator of the motor, and a secondary positioning is performed on aposition between the rotor and the stator using a torque produced bythis magnetic field.

Next, the processing unit 10 controls the driving signal generatingcircuit 11 to produce a rotary pulse signal corresponding to the rotarypulse number based on the determined rotary pulse number, and inputs itinto the driving circuit 12. The rotary pulse signal is applied to themotor of the electronic expansion valve after undergoing a poweramplification by the driving circuit 12 to rotate the motor by an anglecorresponding to the rotary pulse number (step 307).

After the motor of the electronic expansion valve is rotated by an anglecorresponding to the rotary pulse number, in the step 308, theprocessing unit 10 controls the driving signal generating circuit 11 tooutput a third holding current of a third predetermined duration time tothe driving circuit 12, which current is applied to the motor of theelectronic expansion valve after undergoing a power amplification by thedriving circuit 12, a magnetic field is produced between the rotor andthe stator of the motor, and a primary positioning is performed on aposition between the rotor and the stator using a torque produced bythis magnetic field. Then, the driving signal generating circuit 11outputs an additional pulse signal of a second predetermined pulsenumber under control of the processing unit 10, and this additionalpulse signal acts on the motor of the electronic expansion valve afterundergoing a power amplification by the driving circuit 12 to rotate themotor by a tiny angle (step 309). In the step 310, the processing unit10 controls the driving signal generating circuit 11 again to output afourth holding current of a fourth predetermined duration time, whichcurrent is applied to the motor of the electronic expansion valve afterundergoing a power amplification by the driving circuit 12, a magneticfield is produced between the rotor and the stator of the motor, and asecondary positioning is performed on a position between the rotor andthe stator using a torque produced by this magnetic field. In the step311, the processing unit 10 stores the desired valve body opening pulsenumber in the memory to serve as the current valve body opening pulsenumber, and the flow ends at the step 312.

In this embodiment, the first through fourth duration times can be thesame or different, but are all at least 50 milliseconds. Alternatively,each of the first through fourth duration times can be 60 milliseconds,70 milliseconds, 80 milliseconds, 90 milliseconds, 100 milliseconds,etc. However, in order not to overheat the motor, each of the firstthrough fourth duration times had better not exceed 1 second.

In this embodiment, the first predetermined pulse number and the secondpredetermined pulse number are both 1.

In this embodiment, not only a secondary positioning is performed on themotor of the electronic expansion valve before starting the electronicexpansion valve as in the embodiment shown in FIG. 2 to overcome thedefect that the electronic expansion valve cannot be effectively drivendue to an insufficient starting torque of the motor and the defect thatthe start is out of step due to the deviation of the relative positionbetween the rotor and the stator, but also a secondary positioning isperformed on the motor of the electronic expansion valve again afterapplying a rotary pulse number to the motor of the electronic expansionvalve to enhance the torque of the motor to achieve that the rotor ofthe motor of the electronic expansion valve will not be displaced due toa refrigerant pressure change and the like after the stop of the motor.

FIG. 4 shows a flow chart of the drive control method for the electronicexpansion valve according to a further embodiment of the disclosure. Asshown in FIG. 4, as in the step 201, the processing unit 10 receives adesired valve body opening signal of the electronic expansion valve, andobtains a desired valve body opening pulse number from the desired valvebody opening signal. Next, in the step 402, the processing unit 10 readsa current valve body opening pulse number from the memory. Theprocessing unit 10 compares the desired valve body opening pulse numberwith the current valve body opening pulse number (step 403), anddetermines a rotary pulse number of a pulse signal required to rotatethe motor of the electronic expansion valve when the two pulse numbersare different. If the desired valve body opening pulse number is thesame as the current valve body opening pulse number, the flow proceedsto the step 409. If the desired valve body opening pulse number isdifferent from the current valve body opening pulse number, theprocessing unit 10 controls the driving signal generating circuit 11 toproduce a rotary pulse signal corresponding to the rotary pulse numberbased on the determined rotary pulse number, and inputs it into thedriving circuit 12. The rotary pulse signal is applied to the motor ofthe electronic expansion valve after undergoing a power amplification bythe driving circuit 12 to rotate the motor by an angle corresponding tothe rotary pulse number (step 404). Optionally, before the step 404, theprocessing unit 10 controls the driving signal generating circuit 11 tooutput a first holding current of a first predetermined duration time tothe driving circuit 12, which current is applied to the motor of theelectronic expansion valve after undergoing a power amplification by thedriving circuit 12, a magnetic field is accordingly produced between therotor and the stator of the motor, and a primary positioning isperformed on a position between the rotor and the stator using a torqueproduced by this magnetic field.

After the motor of the electronic expansion valve is rotated by an anglecorresponding to the rotary pulse number, in the step 405, theprocessing unit 10 controls the driving signal generating circuit 11 tooutput a third holding current of a third predetermined duration time tothe driving circuit 12, which current is applied to the motor of theelectronic expansion valve after undergoing a power amplification by thedriving circuit 12, a magnetic field is produced between the rotor andthe stator of the motor, and a primary positioning is performed on aposition between the rotor and the stator using a torque produced bythis magnetic field. Then, the driving signal generating circuit 11outputs an additional pulse signal of a second predetermined pulsenumber under control of the processing unit 10, and this additionalpulse signal acts on the motor of the electronic expansion valve afterundergoing a power amplification by the driving circuit 12 to rotate themotor by a tiny angle (step 406). In the step 407, the processing unit10 controls the driving signal generating circuit 11 again to output afourth holding current of a fourth predetermined duration time, whichcurrent is applied to the motor of the electronic expansion valve afterundergoing a power amplification by the driving circuit 12, a magneticfield is accordingly produced between the rotor and the stator of themotor, and a secondary positioning is performed on a position betweenthe rotor and the stator using a torque produced by this magnetic field.In the step 408, the processing unit 10 stores the desired valve bodyopening pulse number in the memory to serve as the current valve bodyopening pulse number, and the flow ends at the step 409.

In this embodiment, the first, third and fourth duration times can bethe same or different, but are all at least 50 milliseconds.Alternatively, each of the first, third and fourth duration times can be60 milliseconds, 70 milliseconds, 80 milliseconds, 90 milliseconds, 100milliseconds, etc. However, in order not to overheat the motor, each ofthe first, third and fourth duration times had better not exceed 1second.

In this embodiment, the second predetermined pulse number is preferably1.

In this embodiment, after applying a rotary pulse number to the motor ofthe electronic expansion valve, a secondary positioning is performed onthe motor of the electronic expansion valve again to enhance the torqueof the motor to achieve that the rotor of the motor of the electronicexpansion valve will not be displaced due to a refrigerant pressurechange and the like after the stop of the motor. Further, beforeapplying the rotary pulse number to the motor of the electronicexpansion valve, the holding current of the first duration time makesthe motor produce a large torque to overcome the resistance, which alsocontributes to the correct start of the electronic expansion valve.

The above contents are only preferred implementation modes of thedisclosure, and it should be noted that those skilled in the art canalso make some improvements and decorations without departing from theprinciple of the disclosure, and these improvements and decorationsshall also be deemed as ones within the scope of protection of thedisclosure.

1. A drive control device for an electronic expansion valve, comprising:a processing unit for receiving a desired valve body opening signal ofthe electronic expansion valve and determining a desired valve bodyopening pulse number according to the desired valve body opening signal,and obtaining a rotary pulse number of a pulse signal required to rotatea motor of the electronic expansion valve based on the desired valvebody opening pulse number and a current valve body opening pulse number;a driving signal generating circuit for producing an additional pulsesignal of a predetermined pulse number and producing a drive pulsesignal of a corresponding pulse number according to the rotary pulsenumber under control of the processing unit, and producing a holdingcurrent of a predetermined duration time under control of the processingunit; and a driving circuit for performing power amplifications on theadditional pulse signal and the drive pulse signal respectively andapplying them to the motor to rotate the motor, and performing a poweramplification on the holding current of the predetermined duration timeoutputted from the driving signal generating circuit and applying it tothe motor to produce a torque that achieves positioning a relativeposition between stator and rotor magnetic fields of the motor.
 2. Thedrive control device according to claim 1, wherein the driving signalgenerating circuit producing a holding current of a predeterminedduration time under control of the processing unit comprises: thedriving signal generating circuit producing a first holding current of afirst predetermined duration time when the processing unit determinesthat the desired valve body opening pulse number is not equal to thecurrent valve body opening pulse number; and the driving signalgenerating circuit producing a second holding current of a secondpredetermined duration time after the driving circuit drives the motoraccording to an additional pulse signal of a first predetermined pulsenumber.
 3. The drive control device according to claim 1, the drivingsignal generating circuit producing a holding current of a predeterminedduration time under control of the processing unit comprising: thedriving signal generating circuit producing a third holding current of athird predetermined duration time after the driving circuit drives themotor according to the drive pulse signal; and the driving signalgenerating circuit producing a fourth holding current of a fourthpredetermined duration time after the driving circuit drives the motoraccording to an additional pulse signal of a second predetermined pulsenumber.
 4. The drive control device according to claim 3, wherein eachof the first through fourth predetermined duration times is 50milliseconds to 1 second.
 5. The drive control device according to claim4, further comprising: a memory for storing the desired valve bodyopening pulse number and using it as the current valve body openingpulse number.
 6. (canceled)
 7. A drive control method for an electronicexpansion valve, comprising the steps of: receiving a desired valve bodyopening signal of the electronic expansion valve, and determining adesired valve body opening pulse number according to the desired valvebody opening signal; applying a first holding current of a firstpredetermined duration time to a motor to produce a torque that achievespositioning a relative position between stator and rotor magnetic fieldsof the motor when the desired valve body opening pulse number isdifferent from a current valve body opening pulse number; applying afirst additional pulse signal of a first predetermined pulse number tothe motor of the electronic expansion valve after performing a poweramplification thereon, and then applying a second holding current of asecond predetermined duration time to the motor to produce a torque thatachieves positioning a relative position between stator and rotormagnetic fields of the motor; and determining a rotary pulse number thatthe motor to be rotated according to the desired valve body openingpulse number and the current valve body opening pulse number, producinga drive pulse signal corresponding to the rotary pulse number based onthe rotary pulse number, and applying the drive pulse signal to themotor of the electronic expansion valve after performing a poweramplification thereon.
 8. The drive control method according to claim 7,wherein receiving a desired valve body opening signal of the electronicexpansion valve and determining a desired valve body opening pulsenumber according to the desired valve body opening signal comprises:using, if the desired valve body opening signal is a pulse number, thepulse number as the desired valve body opening pulse number; orconverting, if the desired valve body opening signal is an angle signal,the angle signal into a pulse number of a pulse signal corresponding tothe angle signal according to a predetermined algorithm, and using it asthe desired valve body opening pulse number.
 9. The drive control methodaccording to claim 7, wherein the current valve body opening pulsenumber is stored in a memory.
 10. The drive control method according toclaim 7, further comprising: storing the desired valve body openingpulse number in the memory to serve as the current valve body openingpulse number.
 11. The drive control method according to claim 7, afterproducing a drive pulse signal corresponding to the rotary pulse numberbased on the rotary pulse number, and applying the drive pulse signal tothe motor of the electronic expansion valve after performing a poweramplification thereon, further comprising: applying a third holdingcurrent of a third predetermined duration time to the motor to produce atorque that achieves positioning a relative position between stator androtor magnetic fields of the motor.
 12. The drive control methodaccording to claim 11, after applying a third holding current of a thirdpredetermined duration time to the motor to produce a torque thatachieves positioning a relative position between stator and rotormagnetic fields of the motor, further comprising: applying a secondadditional pulse signal of a second predetermined pulse number to themotor of the electronic expansion valve, and then applying a fourthholding current of a fourth predetermined duration time to the motor toproduce a torque that achieves positioning a relative position betweenstator and rotor magnetic fields of the motor.
 13. The drive controlmethod according to claim 11, wherein each of the first through fourthduration times is 50 milliseconds to 1 second.
 14. The drive controlmethod according to claim 12, wherein each of the first and secondpredetermined pulse numbers is
 1. 15. A drive control method for anelectronic expansion valve, comprising the steps of: receiving a desiredvalve body opening signal of the electronic expansion valve, anddetermining a desired valve body opening pulse number according to thedesired valve body opening signal; determining a rotary pulse numberthat rotates a motor of the electronic expansion valve according to thedesired valve body opening pulse number and a current valve body openingpulse number, producing a drive pulse signal corresponding to the rotarypulse number based on the rotary pulse number, and applying the drivepulse signal to the motor of the electronic expansion valve afterperforming a power amplification thereon; applying a third holdingcurrent of a third predetermined duration time to the motor afterperforming a power amplification thereon to produce a torque thatachieves positioning a relative position between stator and rotormagnetic fields of the motor; and applying an additional pulse signal ofa second predetermined pulse number to the motor of the electronicexpansion valve after performing a power amplification thereon, and thenapplying a fourth holding current of a fourth predetermined durationtime to the motor after performing a power amplification thereon toproduce a torque that achieves positioning a relative position betweenstator and rotor magnetic fields of the motor.
 16. The drive controlmethod according to claim 15, wherein receiving a desired valve bodyopening signal of the electronic expansion valve and determining adesired valve body opening pulse number according to the desired valvebody opening signal comprises: using, if the desired valve body openingsignal is a pulse number, the pulse number as the desired valve bodyopening pulse number; or converting, if the desired valve body openingsignal is an angle signal, the angle signal into a pulse number of apulse signal corresponding to the angle signal according to apredetermined algorithm, and using it as the desired valve body openingpulse number.
 17. The drive control method according to claim 15, beforedetermining a rotary pulse number making the motor of the electronicexpansion valve rotate according to the desired valve body opening pulsenumber and a current valve body opening pulse number, furthercomprising: applying a first holding current of a first predeterminedduration time to the motor after performing a power amplificationthereon to produce a torque that achieves positioning a relativeposition between stator and rotor magnetic fields of the motor.
 18. Thedrive control method according to claim 15, wherein the current valvebody opening pulse number is stored in a memory.
 19. The drive controlmethod according to claim 15, further comprising: storing the desiredvalve body opening pulse number in the memory as the current valve bodyopening pulse number.
 20. The drive control method according to claim17, wherein each of the first, third and fourth duration times is 50milliseconds to 1 second.
 21. The drive control method according toclaim 15, wherein the second predetermined pulse number is 1.